1. What does grep do?
Junior- A.search text for lines matching a pattern
- B.print the first whitespace-delimited field of each line
- C.count the number of lines in a file
- D.find .log files modified more than 7 days ago
Linux · Shell interview questions
54 real Linux · Shell questions from the System Administration bank, as asked in Indian campus drives and tech interviews. Every question has a verified answer and an AI-tutor explanation on placd — free to start.
1. What does
Junior2. Which command will search text for lines matching a pattern?
Junior- A.grep
- B.cut -d: -f1 /etc/passwd
- C.sed
- D.awk
3. Which statement is correct?
Junior- A.grep — count occurrences of each unique line
- B.grep — process and extract text by fields/columns
- C.grep — print the first whitespace-delimited field of each line
- D.grep — search text for lines matching a pattern
4. What does awk do?
Junior- A.process and extract text by fields/columns
- B.print the first whitespace-delimited field of each line
- C.build and run commands from standard input
- D.find .log files modified more than 7 days ago
5. Which command will process and extract text by fields/columns?
Junior- A.xargs
- B.wc -l file
- C.awk
- D.awk '{print $1}'
6. Which statement is correct?
Junior- A.awk — extract the first colon-delimited field (usernames)
- B.awk — process and extract text by fields/columns
- C.awk — find .log files modified more than 7 days ago
- D.awk — count the number of lines in a file
7. What does sed do?
Junior- A.search text for lines matching a pattern
- B.perform stream text substitution/editing
- C.count the number of lines in a file
- D.process and extract text by fields/columns
8. Which command will perform stream text substitution/editing?
Junior- A.head -n 20 file
- B.wc -l file
- C.sed
- D.find / -name '*.log' -mtime +7
9. Which statement is correct?
Junior- A.sed — perform stream text substitution/editing
- B.sed — count the number of lines in a file
- C.sed — replace all 'foo' with 'bar' in-place
- D.sed — show the first 20 lines of a file
10. What is 2>&1?
Mid- A.the exit code of the last command (0 = success)
- B.append output to a file instead of overwriting it
- C.runs the next command only if the previous one succeeded
- D.redirect stderr to wherever stdout currently points
11. Which term means: "redirect stderr to wherever stdout currently points"?
Mid- A.2>&1
- B.$?
- C.| (pipe)
- D.trap
12. Which statement is correct?
Mid- A.2>&1 — redirect stderr to wherever stdout currently points
- B.2>&1 — append output to a file instead of overwriting it
- C.2>&1 — runs the next command only if the previous one succeeded
- D.2>&1 — strict bash mode: exit on error, unset vars and pipe failures
13. What is $??
Junior- A.a bash builtin that runs code on a received signal (e.g. cleanup on EXIT)
- B.append output to a file instead of overwriting it
- C.the exit code of the last command (0 = success)
- D.sends the stdout of one command to the stdin of the next
14. Which term means: "the exit code of the last command (0 = success)"?
Junior- A.$?
- B.&& operator
- C.| (pipe)
- D.trap
15. Which statement is correct?
Junior- A.$? — strict bash mode: exit on error, unset vars and pipe failures
- B.$? — redirect stderr to wherever stdout currently points
- C.$? — the exit code of the last command (0 = success)
- D.$? — runs the next command only if the previous one succeeded
16. What is >> operator?
Junior- A.the exit code of the last command (0 = success)
- B.a bash builtin that runs code on a received signal (e.g. cleanup on EXIT)
- C.sends the stdout of one command to the stdin of the next
- D.append output to a file instead of overwriting it
17. Which term means: "append output to a file instead of overwriting it"?
Junior- A.>> operator
- B.&& operator
- C.set -euo pipefail
- D.| (pipe)
18. Which statement is correct?
Junior- A.>> operator — redirect stderr to wherever stdout currently points
- B.>> operator — the exit code of the last command (0 = success)
- C.>> operator — a bash builtin that runs code on a received signal (e.g. cleanup on EXIT)
- D.>> operator — append output to a file instead of overwriting it
19. What does cut -d: -f1 /etc/passwd do?
Junior- A.show the first 20 lines of a file
- B.perform stream text substitution/editing
- C.build and run commands from standard input
- D.extract the first colon-delimited field (usernames)
20. Which command will extract the first colon-delimited field (usernames)?
Junior- A.find / -name '*.log' -mtime +7
- B.wc -l file
- C.cut -d: -f1 /etc/passwd
- D.awk
21. Which statement is correct?
Junior- A.cut -d: -f1 /etc/passwd — show the first 20 lines of a file
- B.cut -d: -f1 /etc/passwd — extract the first colon-delimited field (usernames)
- C.cut -d: -f1 /etc/passwd — count the number of lines in a file
- D.cut -d: -f1 /etc/passwd — perform stream text substitution/editing
22. What does sort | uniq -c do?
Junior- A.show the first 20 lines of a file
- B.count occurrences of each unique line
- C.extract the first colon-delimited field (usernames)
- D.search text for lines matching a pattern
23. Which command will count occurrences of each unique line?
Junior- A.sed -i 's/foo/bar/g' file
- B.wc -l file
- C.sort | uniq -c
- D.head -n 20 file
24. Which statement is correct?
Junior- A.sort | uniq -c — process and extract text by fields/columns
- B.sort | uniq -c — count occurrences of each unique line
- C.sort | uniq -c — count the number of lines in a file
- D.sort | uniq -c — show the first 20 lines of a file
25. What does wc -l file do?
Junior- A.process and extract text by fields/columns
- B.count the number of lines in a file
- C.build and run commands from standard input
- D.find .log files modified more than 7 days ago
26. Which command will count the number of lines in a file?
Junior- A.sort | uniq -c
- B.head -n 20 file
- C.wc -l file
- D.cut -d: -f1 /etc/passwd
27. Which statement is correct?
Junior- A.wc -l file — process and extract text by fields/columns
- B.wc -l file — find .log files modified more than 7 days ago
- C.wc -l file — print the first whitespace-delimited field of each line
- D.wc -l file — count the number of lines in a file
28. What does head -n 20 file do?
Junior- A.show the first 20 lines of a file
- B.extract the first colon-delimited field (usernames)
- C.search text for lines matching a pattern
- D.build and run commands from standard input
29. Which command will show the first 20 lines of a file?
Junior- A.wc -l file
- B.awk
- C.head -n 20 file
- D.sed
30. Which statement is correct?
Junior- A.head -n 20 file — extract the first colon-delimited field (usernames)
- B.head -n 20 file — show the first 20 lines of a file
- C.head -n 20 file — print the first whitespace-delimited field of each line
- D.head -n 20 file — process and extract text by fields/columns
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